Method for extending ethernet over twisted pair conductors and to the telephone network and plug-in apparatus for same employing standard mechanics

ABSTRACT

An Ethernet extension device is provided for metro or last mile Ethernet service via twisted pairs as opposed to fiber optics. The Ethernet extension device is implemented as a plug-in extension for existing infrastructure (e.g., in a standard electrical wall box or Type-200™ Mechanics card) that employs lighting and power cross protection required by the telephone companies for Ethernet connectivity to the telephone network (e.g., for connection between a user&#39;s building and a telephone company building over existing outdoor telephone cables).

This application claims the benefit under 35 U.S.C. 119(e) of U.S.provisional application Ser. No. 60/816,867, filed Jun. 28, 2006.

FIELD OF THE INVENTION

The present invention relates generally to providing Ethernet accessusing existing communications infrastructure. More particularly, aplug-in Ethernet extension apparatus and method of using same areprovided to extend Ethernet over twisted pair and to provide Ethernetconnectivity to the telephone network via existing copper wireinfrastructure using standard mechanics such as a standard electricalwall box or standard telecommunications equipment shelf card.

BACKGROUND OF THE INVENTION

Existing Ethernet connections are limited to less than 350 feet to avoidsignal degradation. While Ethernet extension devices are available toextend this range, these devices are generally packaged as “desktopboxes” otherwise known as “pizza box” solutions that increase clutter,increase installation complexity and/or can be removed by unauthorizedpersonnel. WiFi wireless extensions are also limited to a few hundredfeet in range, often have the same disadvantages of desktop or set topboxes, and raise security and interference concerns. A need thereforeexists for an Ethernet extension technology that is packaged as aplug-in or standard electrical wall box to overcome these disadvantages.

In addition, according to dBrn Associates, Inc., an independenttelecommunications consulting firm, “95% of data traffic begins and/orends on an Ethernet interface.” It is not surprising, then, thatEthernet service offerings are growing while other data servicesstagnate. AT&T's Ethernet business grew by 100% in 2004.

Since common Ethernet speeds of 10 and 100 Mb/s are significantly fasterthan T1, which is currently the highest universally supported speed oncopper, fiber optics is the primary means of providing Ethernetconnectivity. Ethernet over fiber is beginning to have an impact ontraditional SONET fiber transport. In a June 2005 report, theInformation Data Corporation (IDC) (i.e., a subsidiary of InformationData Group, a global technology media, research, and events company)predicted that “the migration from . . . SONET . . . to Ethernet is wellunder way. Growth over the next five years will be substantial and metro[last mile] Ethernet represents one of the most significantopportunities in wireline telecom infrastructure.” IDC predicts that themetro Ethernet market will surpass the metro SONET market by 2010.

Yet, for all of the merits of fiber optics, and even considering newefforts to provide residential fiber service, little recent progress hasbeen made to serve additional business locations with fiber optics.Fiber optics continues to reach less that 15% of domestic commercialsites. In fact, of the 750,000 business-use buildings in this countrycontaining more than 20 workers, only about 5% have access to fiberoptics, according to Ryan Hankin Kent (RHK) which providestelecommunications consulting.

Many companies now offer Ethernet-over-copper equipment products. Whileeach has viable technology and most have had some market success, theproducts are either platform-based or box-based, and lack theplug-and-play simplicity of T1 and HDSL repeaters. To telephonecompanies (hereinafter referred to as “Telcos”), these products appearas yet another “network solution” or “pizza box” rather than a plug-inextension for existing infrastructure.

Products that provide Ethernet over twisted pair have been in existencefor several years. Most are “pizza box” or shelf-based systems designedfor efficient delivery of multiple Ethernet links. Some take the form ofIntegrated Access Devices (LADs). Others are designed for Multi-TenantUnits (MTUs) to distribute Ethernet to multiple users within a building.With few exceptions, vendors have generally marketed to CompetitiveLocal Exchange Carriers (CLECs) and smaller Incumbent Local ExchangeCarriers (ILECs) to avoid the long standardization cycles and thedaunting relationship development required to sell to the RBOCs. Oneexception is XEL, recently purchased by Verilink. XEL's longrelationship with GTE drove Verizon standardization of the Shark LAD.The Shark IAD provides Ethernet, low speed data and POTS/SPOTS over atwo T1 link. The Verizon GTE acquisition paved the way for significantuse of the Shark IAD (i.e., now a Verilink product) throughout theVerizon network.

Over all, however, such integrated products are problematic whencompared with traditional RBOC “one-at-a-time” discrete CO or DLC-basedtopologies in terms of cost, administration and maintenance. However,for CLECs, LAD-type devices permit use of a leased T1 line to carrymultiple voice and data circuits less expensively than individuallyleasing the same services from the incumbent Local Exchange Carrier forresale to a prospective customer.

DSL provides Ethernet-based internet access at relatively low cost.However, while a number of companies now use “Business DSL” for webaccess, such activity is generally segregated from telephony andcorporate LAN or WAN data. Companies exist which offer web/IP-basedvoice service (e.g., Vonage) that some businesses now use, but security,reliability and, in some cases, access speed concerns keep DSL andexisting DSL infrastructure from being considered a viable alternativeto trusted Leased Lines, Frame Relay and ATM that offer Service LevelAgreement (SLA) guarantees.

Thus, a need exists for an Ethernet extension device for providing metroor last mile Ethernet service via twisted pairs as opposed to fiberoptics. Further, a need exists for an Ethernet-over-copper solution thathas the plug-and-play simplicity of T1 and HDSL.

Finally, there exist Ethernet-over-copper products with similarfunctions (e.g., products offered by Patton Electronics in Germantown,Md.). These products, however, are not intended for mounting in a wallbox, and they are not intended for interfacing to the phone network.They do not provide, for example, telco-required lightning protectionwhich would permit them to interface to the telephone network. Othercompetitors such as Actellis, Lucent, Cisco, and others do havetelephone network-compatible interfaces; however, they are large,expensive systems, and difficult to install. Thus, a need exists for aEthernet-over-copper extension device that has plug-in capability (e.g.,is implemented as a standard electrical wall box or plug-in card), andthat can interface with the telephone network (i.e., has certificationfor lighting and power cross protections).

SUMMARY OF THE INVENTION

The above disadvantages are avoided and other advantages are realized byan apparatus and method according to the present invention. According toan exemplary embodiment of the present invention, Ethernet extensiontechnology is implemented in a standard plug-in telecommunicationsequipment shelf card or a standard electrical wall box to overcome thesedisadvantages.

According to an aspect of an exemplary embodiment of the presentinvention, an Ethernet extension device is configured to provide metroor last mile Ethernet service via twisted pairs as opposed to fiberoptics.

According to another aspect of an exemplary embodiment of the presentinvention, an Ethernet extension device is implemented as a plug-inextension for existing infrastructure (e.g., in a standard electricalwall box or Type-200™ or Type-400™ Mechanics card) that employs lightingand power cross protection required by the telephone companies forEthernet connectivity to the telephone network (e.g., for connectionbetween a user's building and a telephone company building over existingoutdoor telephone cables).

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more readily understood with reference to theembodiments thereof illustrated in the attached drawing figures, inwhich:

FIG. 1 is a block diagram of an Ethernet extension device constructed inaccordance with an exemplary embodiment of the present invention;

FIGS. 2 and 3 are schematic diagrams of lighting and power crossprotection-type components employed by an Ethernet extension deviceconstructed in accordance with exemplary embodiments of the presentinvention;

FIGS. 4A and 4B are, respectively, a side elevational view of anEthernet extension device implemented as a plug-in card, and a frontelevational view of the plug-in card faceplate in accordance with anexemplary embodiment of the present invention;

FIGS. 5A, 5B, 5C, 5D and 5E are, respectively, front elevational,perspective, side, front and top views of the faceplate depicted in FIG.4B;

FIGS. 6A, 6B, 6C and 6D are perspective views of illustrative standardelectrical wall boxes in which an Ethernet extension device can beimplemented as a plug-in wall box-type device in accordance with anexemplary embodiment of the present invention;

FIG. 7 depicts standard electrical wall box-type Ethernet extensiondevices connected in accordance with an exemplary embodiment of thepresent invention;

FIGS. 8A, 8B, 8C, 8D and 8E are block diagrams of different applicationsfor an Ethernet extension device implemented as a plug-in device inaccordance with exemplary embodiments of the present invention; and

FIG. 9 depicts an exploded view of an illustrative standard electricalwall box in which an Ethernet extension device can be implemented as aplug-in wall box-type device as shown in FIG. 6 a, vent holes, a heatsink and a face plate in accordance with an exemplary embodiment of thepresent invention.

In the drawing figures, it will be understood that like numerals referto like features and structures.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The matters defined in the description such as a detailed constructionand elements are provided to assist in a comprehensive understanding ofexemplary embodiments of the invention. Accordingly, those of ordinaryskill in the art will recognize that various changes and modificationsof the embodiments described herein can be made without departing fromthe scope and spirit of the invention. Also, descriptions of well-knownfunctions and constructions are omitted for clarity and conciseness.

As will be described in more detail below, exemplary embodiments of thepresent invention provide Ethernet extension devices that are lowinitial cost, use standard mechanics and are simple to use whileproviding comprehensive capabilities. For example, exemplary embodimentsof the Ethernet extension devices of the present invention allow forEthernet connectivity to twisted pair within a building and, moreimportantly, to the telephone network (i.e., via wires that leave thebuilding). In accordance with an exemplary embodiment of the presentinvention, an Ethernet extension device is implemented as a plug-inextension for existing infrastructure (e.g., in a standard wall box orType-200™ or Type-400™ Mechanics card) and employs lighting and powercross protection required by the telephone companies. This is incontrast to certain existing Ethernet extension devices that do notprovide requisite protection for interfacing with the telephone network.

FIG. 1 depicts a block diagram of an exemplary embodiment of the presentinvention. The components in the block diagram can be provided indifferent plug-in type structures (e.g., standard electrical wall boxesor Type-200™ or Type-400™ Mechanics or other standard telecommunicationsequipment shelf card), as depicted in FIGS. 4-6. As shown in FIG. 1,RJ45 is a connector 12. It is the standard connector used for anEthernet interface.

With further reference to FIG. 1, a physical interface PHY 14 isprovided. The physical interface PHY 14 is preferably an integratedcircuit that receives the electrical signal on the Ethernet cableconnected to the connector 12 and converts it to standard digitallevels. The Ethernet PHY 14 implements the physical layer of the sevenlayer OSI model, and provides the physical link to the 10/100BaseTtwisted pair interface. As described below, an Ethernet Media AccessController (MAC) 16 is implemented within an Ethernet transceiver 18.The MAC 16 and PHY 14 are preferably linked via a Media IndependentInterface (MII).

The Ethernet transceiver 18 in FIG. 1 is preferably a single integratedcircuit that implements several functions. The MAC 16 implements thestandard function of monitoring for communication collisions on acorresponding local area network (LAN) and retransmitting corrupted datapackets. The High-level Data Link Control (HDLC) interfaces 20 and 30provide a serial data interface. These devices 20 and 30 are responsiblefor collecting data into packets for transmission, adding error checkingoverhead, and generally tracking the progress data transmission. Thereceiver side of the HDLC interfaces 20 and 30 find the beginning andend of packets, check for errors, strip the overhead, and provide theuser data to a processor described below. The HDLC format is used as aconvenient mechanism to transfer data between the Ethernet transceiver18 to an SHDSL transceiver 24 integrated circuit that is also shown inFIG. 1. The HDLC format is especially convenient since Ethernet uses theHDLC format to convey frames of data over the LAN. A processor interface22 is also provided in FIG. 1 that allows for controlling the Ethernettransceiver 18 from a microprocessor such as the host processor 26embedded within the SHDSL transceiver 24 described below.

The SHDSL transceiver 24 integrated circuit in FIG. 1 provides data,modulated onto a carrier toward the digital subscriber loop (DSL)interface (e.g., DSL core 28) shown on the right side of the blockdiagram in FIG. 1. The device 24 also preferably comprises an embeddedhost microprocessor 26 that serves as the master controller for thefunctions performed by the Ethernet extension device 10 of the presentinvention. The Ethernet transceiver 18 and the SHDSL transceiver 24 arepreferably provided by Metalink LTD located in Yakum, Israel, but otherproviders of these technologies are available.

There are many varieties of DSL available today including, but notlimited to, asymmetric digital subscriber loop (ADSL). ADSL is what thetelephone company often uses to deliver DSL service to a home. The datarate into the home is much faster than the data rate out of the home, soit is called asymmetric. Another recent development of ADSL, that is,ADSL2+, can provide faster speeds, up to 12 Mbps, of data into the homeon two twisted pair wires. In contrast, High bit-rate DSL (e.g., HDSL,HDSL2, and HDSL2+) are symmetrical data delivery technologies that arefrequently used to replace standard T1 lines which operate at 1.544 Mbpsin both directions. HDSL2 has the advantage of requiring only onetwisted pair cable to carry data instead of the two twisted pairs cablesrequired by T1. Thus, the telephone company can add more T1 service to asite without installing additional wire. Symmetric High bit-rate DSL orSHDSL can operate at various bit rates. The bit rate will changedepending on the quality of the copper line. A long or noisy line cannotcarry as much data as a short, quiet line. The SHDSL algorithms makemeasurements of the line at startup to determine the fastest practicaldata rate. Sometimes, SHDSL is referred to as G.SHDSL after the standardfor SHDSL published by the International Telephony Union (ITU). The ITUspecification is number G.991.2 and the “G.” from the specification isfrequently prefixed to the SHDSL acronym. In any event, the SHDSLstandard is the preferred standard used for implementing an exemplaryembodiment of the present invention.

During establishment of an optimum data rate, the SHDSL transceiver 24in FIG. 1 modulates data preferably using Trellis Coded Pulse AmplitudeModulation (TC-PAM). The modulated analog signal is provided to theanalog front end (AFE) 32 also shown in FIG. 1. The AFE 32 is a robustamplifier for the transmitter side of the SHDSL transceiver 24 and asensitive amplifier on the receive side. A hybrid balance network at theAFE 32 and digital echo-cancellation techniques within the SHDSLtransceiver 24 are used to separate the signals in the transmit andreceive paths of the SHDSL transceiver 24.

A transformer XMFR 34 is depicted at the far right of the block diagramin FIG. 1. The XFMR 34 is an interface to the telephone network. TheXMFR 34 described in more detail below in connection with FIG. 2.

The above-described components in FIG. 1 also operate to send signalsreceived via the Tip and Ring inputs to the XMFR 34 to the Ethernetinterface (e.g., the RJ45 connector 12). For example, the HDLC interface20 of the Ethernet transceiver 18 receives data from the SHDSLtransceiver 24 and organizes packets and adds overhead as needed forEthernet transmission.

The host processor 26 in the SHDSL transceiver 24 depicted in FIG. 1 ispreferably a microprocessor. The flash memory 36 and Static RandomAccess Memory (SRAM) 38 are memory used by the microprocessor 26. Theflash memory 36 contains instructions and fixed data that are retainedeven when power is removed. The SRAM 38 is updated by the host processor26 almost instantly, but the contents are lost when power is removed.

The Complex Programmable Logic Device (CPLD) 40 in FIG. 1 is preferablya digital logic circuit designed to coordinate components shown inFIG. 1. The logic allows the microprocessor or host processor 26 tocontrol front panel LEDs 42 and read the state of various switches 44 onthe front panel described below in connection with FIGS. 5A through 5E.The CPLD 40 also provides buffering of the address and data busesbetween the host processor 26 and the Ethernet transceiver 18.

In accordance with an exemplary embodiment of the present invention, thecomponents in FIG. 1 are implemented using Type 200™ Mechanics, atrademark of Westell, Inc., or similar card configuration, and ishereinafter referred to as the “EE2.” The EE2 implementation preferablyhas two SHDSL ports for double the throughput. In accordance withanother exemplary embodiment of the present invention, the components inFIG. 1 are implemented in a standard electrical wall box hereinafterreferred to as the “EEB.” The EE2 preferably collects performance datawhich the EEB version does not do since there is little room in the EEBfor another port to a personal computer (PC) to report any performancedata. The EE2 has two relays that will close on certain error conditionsto indicate an alarm. This is often used in a telephone central officeapplication to light a light or ring a bell. It is preferably not usedin the EEB version. Finally, the EEB preferably uses a low voltage DCpower input (such as 12 VDC) from a small power-supply brick withintegral male plug designed to plug directly into a wall outlet, whilethe EE2 is preferably specified to have a 48 v input (i.e., the typicalpower source in the telephone company applications).

As stated above, there exist Ethernet-over-copper products with similarfunctions to those described with respect to FIG. 1 (e.g., productsoffered by Patton Electronics in Germantown, Md.). These products do notprovide features required by telephone companies such as lightningprotection to interface to the telephone network. Thus, these productscannot be used to connect to outdoor telephone lines. Further, they arenot intended for mounting in a wall box. In accordance with an aspect ofan exemplary embodiment of the present invention, the telecommunicationsports of the SHDSL transceiver 24 and the 10/100 BaseT Ethernettransceiver 18 shown in FIG. 1 are designed to meet the electricalsafety requirements of GR-1089-CORE Issue 3, October 2002. Per GR-1089,the two-wire SHDSL ports of the SHDSL transceiver 24 of FIG. 1 arepreferably Type 3, while the four-wire Ethernet port of the Ethernettransceiver 18 is preferably Type 4. Type 3 ports are defined asequipment ports directly connected to metallic tip and ringoutside-plant conductors, including lines that leave the premises andare intended to be located on customer premises. Type 4 ports aredefined as equipment ports intended to be located on customer premisesthat do not directly connect to metallic tip and ring outside-plantconductors, but may serve intra-building metallic tip and ringconductors only.

Type 3 equipment ports must pass both First and Second-Level LightningSurge tests, as well as both First and Second-Level AC Power Fault testsas described in GR-1089-CORE. In order to pass the First-Level surge andpower fault tests, the equipment under test (EUT) must not be damagedand must continue to operate properly following the complete battery oftests. The EUT is considered to pass the Second level surge and powerfault tests if it does not become a fire, fragmentation, or electricalsafety hazard during any of the tests, with the added stipulation thatwiring external to the EUT remain undamaged following the Second levelpower fault tests.

Type 4 equipment ports must pass Intra-Building Lightning Surge testsand Second-Level Intra-Building AC Power Fault tests as described inGR-1089-CORE. In order to pass the Intra-Building surge tests, theequipment under test (EUT) must not be damaged and must continue tooperate properly following the complete battery of tests. The EUT isconsidered to pass the Second level Intra-Building power fault tests ifit does not become a fire, fragmentation, or electrical safety hazardduring any of the tests, and the wiring external to the EUT remainsundamaged.

One port 46 of the two aggregate SHDSL ports of an Ethernet extensiondevice 10 in accordance with an exemplary embodiment of the presentinvention is shown in the schematic diagram of FIG. 2 which depicts theAFE and the XFMR 34 of FIG. 1 in greater detail. The other SHDSL port(not shown) can also be implemented as shown in FIG. 2.

Components CR11, CR12, and U18 in FIG. 2 provide the over-voltageprotection that allows the unit to survive and continue to operateproperly following the battery of First-Level Lightning Surge andFirst-Level AC Power Fault tests. CR11 and CR12 are also instrumental inallowing the device 10 to meet the Second-Level Lightning Surge andSecond-Level AC Power Fault requirements. Fuses F2 and F3 operate inconjunction with CR11 and CR12 to protect external wiring from damageduring the battery of Second-Level AC Power Fault tests, as well asassure that the EUT (e.g., device 10) does not become a fire,fragmentation, or electrical safety hazard. The physical isolation ofthe primary and secondary windings on the XFMR 34 of FIG. 1 (i.e.,indicated as T2 in FIG. 2) also provides some protection againstlongitudinal (common mode) surges.

Components CR11 and CR12 depicted in FIG. 2 are preferably sidactordevices that provide the secondary level of over-voltage protection forthe two-wire SHDSL port 46. Note that the primary level of protection islocated external to the unit as is the usual practice of telephonecompanies. Under normal operating conditions, these sidactor devicesCR11 and CR12 exhibit a high-impedance characteristic that results inminimal degradation of the balanced SHDSL signal at the port. When anover-voltage condition occurs at the port between the Tip (edge-fingerpin 7 of the standard-mechanics Type 200™ printed circuit board) andframe-ground (FGND) and/or the Ring (edge-finger pin 13 of thestandard-mechanics Type 200™ printed circuit board) and frame-ground,the corresponding sidactor crowbars into a low-impedance state. Theresulting surge current is thereby shunted to frame-ground through thesidactor. The sidactor(s) remain in the low-impedance state until theshunted current falls below the holding-current threshold, at whichpoint the device 10 transitions back to a high-impedance state. Thespecific devices chosen for CR11 and CR12 crowbar at a break-overvoltage and have a holding current limit selected for optimizedoperation in accordance with an exemplary embodiment of the presentinvention.

Component U18 in FIG. 2 is preferably a combination low-capacitancesteering diode/transient voltage suppressor (TVS) array combination(hereinafter referred to as a “diode array”) that provides a tertiarylevel of over-voltage protection on the SHDSL port 46. Thelow-capacitance characteristic makes the diode array present a highshunt-impedance under normal operating conditions, which results inminimal degradation of the SHDSL signal. The diode array U18 isreferenced to the supply rails for the SHDSL analog front-end IC 32(U17) that is being protected. Positive surges in excess of the 5 Vsupply rail (CY_AFEVDD) are shunted to the 5 V supply rail by thesteering diodes component of the diode array. Similarly, negative surgesbelow the ground-reference rail (GND) are shunted to ground by thesteering diodes. Under normal operating conditions, the TVS diodecomponent of the diode array appears to be an open-circuit, but willbegin to conduct when the reverse bias between the supply rails exceeds5 V. The TVS diode then prevents bounce of the supply rails that mayoccur when surge currents are diverted to the rails by the steeringdiodes array.

Components F2 and F3 in FIG. 2 are preferably fuses that have beenspecially designed by the manufacturer to meet the lightning surge andpower fault requirements of GR-1089-CORE. As described previously, CR11and/or CR12 will crowbar into a low-impedance state during anover-voltage condition, thereby shunting the resulting current toframe-ground. Current that enters the Tip (edge-finger pin 7 of thestandard-mechanics Type 200™ printed circuit board) passes through fuseF3 before being shunted to frame-ground by CR12; likewise, current thatenters the Ring (edge-finger pin 13 of the standard-mechanics Type 200™printed circuit board) passes through fuse F2 before being shunted toframe-ground by CR11. Currents shunted to frame-ground during theSecond-Level AC Power Fault tests are of sufficient magnitude andduration so as to cause fuses F2 and F3 to open, thereby protecting thewiring external to the unit, as well as assure that the EUT does notbecome a fire, fragmentation, or electrical safety hazard fuses. FusesF2 and F3 are designed not to open during the test conditions presentedby the First- and Second-Level Lightning Surge and First-Level AC PowerFault tests.

In accordance with an exemplary embodiment of the present invention, the10/100BaseT Ethernet port 48 of the Ethernet transceiver 18 (FIG. 1) inthe Ethernet extension device 10 of the present invention is depicted inmore detail in the schematic of FIG. 3. FIG. 3 illustrates the PHY (U20)14 described above as connected to the Ethernet transceiver. The RJ45connector 12 described in FIG. 1 is shown as J4 in FIG. 3. ComponentsU23, U24, U21, and U22 provide the over-voltage protection that allowsthe Ethernet extension device 10 of the present invention to survive andcontinue to operate properly following the battery of GR-1089-COREIntra-Building Lightning Surge tests. U23 and U24 are also instrumentalin allowing the device 10 to meet the GR-1089-CORE Second-LevelIntra-Building AC Power Fault requirements. Fuses F4, F5, F6, and F7operate in conjunction with U23 and U24 to protect external wiring fromdamage during the battery of GR-1089-CORE Second-Level Intra-Building ACPower Fault tests, as well as to assure the EUT (e.g., device 10) doesnot become a fire, fragmentation, or electrical safety hazard. Thephysical isolation of the primary and secondary windings on transformerdevice T3 also provides protection against longitudinal (common mode)surges.

Components U23 and U24 in FIG. 3 are preferably combinationlow-capacitance steering diode/TVS array combinations (hereinafterreferred to as “diode arrays”) that provide a secondary level ofover-voltage protection on the four-wire 10/100BaseT Ethernet port(e.g., J4 or RJ45 connector 12). U23 protects the transmit side of thefour-wire Ethernet interface 12, while U24 protects the receive side.The low-capacitance characteristic makes the diode arrays present a highshunt-impedance under normal operating conditions, which results inminimal degradation of the differential Ethernet signals that arepresent on both the transmit and receive sides of the interface (e.g.,connector 12 of transceiver 18). When an over-voltage condition thatexceeds the TVS diode breakdown voltage occurs on either the transmit orreceive side of the port J4, the corresponding diode array clamps thedifferential voltage between the inputs. The resulting surge current isthereby shunted through the respective diode array. The specific deviceschosen for U23 and U24 begin to breakdown at a voltage optimized forthis circuit protection.

Components U21 and U22 of FIG. 3 are preferably combinationlow-capacitance steering diode/TVS array combinations (hereinafterreferred to as “diode arrays”) that provide a tertiary level ofover-voltage protection on the 10/100BaseT Ethernet port. U21 protectsthe transmit side of the four-wire Ethernet interface 12, while U22protects the receive side of interface 12. The low-capacitancecharacteristic makes the diode arrays present a high shunt-impedanceunder normal operating conditions, which results in minimal degradationof the Ethernet signals that are present on both the transmit andreceive sides of the interface. The diode arrays are referenced to thesupply rails for the Ethernet PHY device 14 (U20) that is beingprotected. Positive surges in excess of the 3.3 V supply rail (P3_(—)3V)on either the transmit or receive side of the port 12 are shunted to the3.3 V supply rail by the corresponding steering diodes array. Similarly,negative surges below the ground-reference rail (GND) on either transmitor receive side of the port 12 are shunted to ground by thecorresponding steering diodes. Under normal operating conditions, theTVS diode appears to be an open-circuit, but will begin to conduct whenthe reverse bias between the supply rails exceeds 3.3 V. The TVS diodethen prevents bounce of the supply rails that may occur when surgecurrents are diverted to the rails by the steering diodes.

Components F4, F5, F6, and F7 of FIG. 3 are fuses that have beendesigned by the manufacturer to meet the lightning surge and power faultrequirements of GR-1089-CORE. As described previously, U23 and U24 shuntsurge currents that result from differential over-voltage conditions onthe transmit and receive sides of the four-wire Ethernet port 12,respectively. Surge currents shunted by U23 pass through fuse F4 andfuse F5, while those shunted by U24 pass through fuse F6 and fuse F7.Currents shunted by U23 and U24 during differential over-voltageconditions of the Second-Level Intra-Building AC Power Fault tests areof sufficient magnitude and duration so as to cause fuses F4, F5, F6 andF7 to open, thereby protecting the wiring external to the unit, as wellas assure that the EUT does not become a fire, fragmentation, orelectrical safety hazard. Fuses F4, F5, F6, and F7 are designed not toopen during the test conditions presented by the GR-1089-COREIntra-Building Lightning Surge tests.

FIGS. 4A and 4B illustrate an exemplary embodiment of the Ethernetextension device 10′ of the present invention implemented in a Type 200™Mechanics card 50. FIG. 4A is a side view of the card 50 showing thecircuit components described above in connection with FIGS. 1-3 thereon,among other components. The front panel 52 shown in FIG. 4B is describedin more detail with respect to FIGS. 5A through 5E. It is to beunderstood that the Ethernet extension device 10′ of the presentinvention can be implemented in essentially any telecommunicationsequipment standard mechanics plug-in card and therefore realizes anumber of advantages over set-top box or “pizza” box Ethernet extensionsor other network solutions such as simplified installation, less clutterand lower initial cost. For example, the plug-in card-type Ethernetextension device 10′ of the present invention can be a single-widthstandard mechanics Type 3192 card.

As shown in FIGS. 5A through 5E, a plug-in card-type Ethernet extensiondevice 10′ configured in accordance with an exemplary embodiment of thepresent invention preferably has an RJ45 Ethernet interface jack 12 onthe face plate or front panel 52 thereof. The RJ45 interface 12preferably provides automatic Media Dependent Interface Crossover (MDIX)so that users can use either a straight-through or crossover Ethernetcable. The plug-in card-type Ethernet extension device 10′ also hasswitches 44 and indicators 42 such as light emitting diodes (LEDs).

A printed-circuit-board mounted 5-position DIP switch 44 is preferablyprovided on the plug-in card-type Ethernet extension device 10′ of thepresent invention as shown in FIG. 4A. Position 1 serves to enableautomatic configuration of the Ethernet port 12 such thatauto-negotiation of both data-rate and duplex and the automatic MDI-Xfeature are either simultaneously enabled or disabled. The two switchpositions can be labeled AUTO and MAN. Position 2 selects a 10 or 100BaseT Ethernet rate if the AUTO switch is set to MAN. The two switchpositions can be labeled 10 and 100. Position 3 selects half- orfull-duplex operation if the AUTO switch is set to MAN. The two switchpositions can be labeled HALF and FULL. Position 4 selects eitherCentral Office (line-terminating) or Remote Terminal(network-terminating) operation. The two switch positions can be labeledLT and NT. Position 5 selects 1 pair or 2 pair operation. If single pairoperation is selected, Pair 1 used. The two switch positions can belabeled 1 and 1+2. These switches help to assure that an exemplaryEthernet extension device 10 constructed in accordance with anillustrative embodiment of the present invention is applicable toexisting equipment of a broad range of Ethernet users as is required bya telephone company to provide uniform services to their customer base.

With continued reference to FIGS. 4A and 4B and FIGS. 5A through 5E, thefaceplate 52 can preferably include the following LEDs: a UNIT LED thatis Red for unit malfunction, and Green for normal unit operation; a LINKLED that is Green for normal Ethernet link operation and off to indicateEthernet link failure; an ACT LED to convey the presence of datatransfer activity on the Ethernet link (e.g., flashes or is steadyyellow to indicate activity, and off otherwise); an AUTO LED that isGreen to indicate that the AUTO DIP switch is in the AUTO position andoff otherwise; a LT LED that is Green to indicate that the correspondingoption DIP switch is in the LT (Central Office operation) position andoff otherwise; OSP 1 and OSP 2 LEDs to indicate the status of each SHDSLwire pair (e.g., Green indicates conditions are normal, Yellow indicateslink-up with the far end unit is in progress, and Red indicates failureof the SHDSL link). A DB9 Craft Port may be included to provide accessto performance monitoring data collected from the SHDSL transceiver bythe Host Processor. The −48 VDC power input is provided with transientvoltage and polarity protection to further suit telephone companystandard-mechanics applications.

DC contact closure alarming is preferably provided on the plug-incard-type Ethernet extension device 10′ in accordance with an exemplaryembodiment of the present invention. Two DC contact closure alarms areconnected to the edge connector as follows: Near-end Alarm: pins 5(Tip1) & 15 (Ring1); and Far-end Alarm: pins 49 (Ring) & 55 (Tip). Thesepin numbers refer to those found on standard Type 200™ mechanics. Anear-end failure (either or both telephone company Outside Plant (OSP)pair(s) or Ethernet port alarm causes a contact closure between edgeconnector pins 5 and 15. A far-end failure causes a contact closurebetween edge connector pins 49 and 55. A unit failure causes both pairsof alarm contacts to close. A power failure causes both pairs of alarmcontacts to close.

The RJ45 jack 12 and Ethernet Activity LED 42 are preferably positionedin the upper part of the faceplate 52 and the DIP switch 44 and (ifincluded) DB9 connector in the bottom so that the Ethernet extensiondevice 10′, when incased in a locking cover enclosure, can provide useraccess to only the Ethernet port 12. It is desirable but not requiredthat the LEDs 42 be visible.

In accordance with another exemplary embodiment of the presentinvention, an Ethernet extension device 10″ is implemented in a standardelectrical wall box 54 such as a RACO 509 or similar standard electricalwall box or Carlon SC100RR or similar low voltage wall bracket, as shownin FIGS. 6A through 6D. The Ethernet extension device 10″ comprises thecomponents described above in connection with FIGS. 1, 2 and 3 packagedin a standard electrical wall box to avoid site clutter, improve deviceand connection security and simplify use. The exemplary plug-inembodiment of the present invention as a standard electrical wall box10″ allows for installation by electrical contractors or others besideshigher paid IT professionals to reduce business costs. The wall box-typeEthernet extension device 10″ is designed to preferably be a low voltageinsert for standard 2 inch×3 inch electrical boxes to specificallyaddress the non-telco electrical contractor market. As shown in FIG. 7,a low voltage DC power supply 56 is provided via a wall transformer, asopposed to the −48 VDC power input preferred by telephone companies.

With reference to FIG. 9, the standard electrical wall box-type Ethernetextension (EEB) device 10″ illustrated in FIG. 6 A can incorporate awall face plate insert of standard dimension for access via openings 64to a RJ45 connector 12 and a DC power jack 58 which are mounted to thefront of the EEB device assembly so that a conventional rectangular faceplate 66 can be used to complete installation. The face plate insertpreferably comprises vent holes 65 and a heat sink 62 to reduce heatgenerated by components of device 10. The EEB device 10″ can beoptionally configured for local or remote operation so that the sameunit can be used at either end of a circuit, as shown in FIG. 7, withremote power leads 60 being provided. One twisted pair interface via a2-position screw terminal block is connected to the EEB device assembly.In use, a twisted pair is routed into the rear of the wall box thenattached to the EEB device via this screw terminal strip. The EEB deviceis then mounted to the wall box with two standard screws.

SHDSL technology employed in the standard electrical wall box-typeEthernet extension (EEB) device 10″ of the present invention providescompatibility with existing building circuits with a range of up to 3kFt. (26 Gauge) with a data rate of up to 2.3 Mb/s. An RJ45 Ethernetjack is soldered to the EEB device. The RJ45 interface 12 providesautomatic Media Dependent Interface Crossover (MDIX) so that users canuse either a straight-through or crossover Ethernet cable. A portactivity LED 44 that is on continuously or flashes yellow to indicateEthernet activity may be included. A unit LED that is off if the unit isnot powered, red if the unit malfunctions, yellow if it is not properlyconnected to a far end Ethernet extension device, and green otherwisemay also be included. The RJ45 jack 12 is preferably wired in aconventional way as follows:

Position 1: Rx+ (Receive Tip)

Position 2: Rx− (Receive Ring)

Position 3: Tx+ (Transmit Tip)

Position 4: Unused

Position 5: Unused

Position 6: Tx− (Transmit Ring)

Position 7: Unused

Position 8: Unused

The electrical wall box-type EEB device 10″ performs auto-negotiationfor 10 or 100 BaseT Ethernet rate. A standard, inexpensive, AC to DCwall transformer 56 is used to power the EEB device via a connector 58soldered to the EEB device assembly that appears through the faceplate52. A 2-position screw terminal positioned on the side of the EEB devicecan provide an alternate means of making the power connection or toremotely power a second EE device over limited distances via one or moreadditional twisted pair(s). Unlike the card-type Ethernet extensiondevice 10′, no craft port, DC contact closure alarms or compatibilitywith span power plug-ins are preferably provided for the EE2 device 10′.

The plug-in card-type Ethernet extension device 10′ and the standardwall box-type Ethernet extension device 10″ described herein asexemplary embodiments of the present invention can be advantageouslyused by companies providing telecommunication services (RBOCs, CLECs,ILECs), distributors and end users (e.g., IT, industrial, utility andcommercial applications) alike. These devices are small enough to fitinto standard electrical wall boxes, as well as in the smallest oftelephone closets, Digital Loop Carrier (DLC) remotes or Next GenerationDLC (NGDLC) cabinets. For example, the single plug-in card can bedimensioned for deployment in a single card slot in a shelf of atelecommunications equipment bay (e.g., card dimensions that do notexceed an overall height of about 5.6 inches, and overall width of about1.4 inches, and an overall depth of about 6 inches). Further, unlikemany existing Ethernet extension solutions, the Ethernet extensiondevices of the exemplary embodiments of the present invention allow fornot only Ethernet over twisted pair but also Ethernet connectivity tothe telephone network (e.g., connection between a user's building and atelephone company building over existing outdoor telephone cables) sincethe devices have the protection components required by the telephonecompany.

FIGS. 8A through 8E depict other implementations of Ethernet extensiondevices 10 in accordance with exemplary embodiments of the presentinvention to accommodate campus, industrial, network, and buildingEthernet extension applications, as well as to provide Ethernet-to-DS1service conversion for use with exiting TDM networks. As shown in FIG.8A, a campus extension using 1 or 2 twisted pairs is provided using, forexample, a card-type Ethernet extension device 10′ (e.g., standard Type200™ or 3192 mechanics), as described above in connection with FIGS. 4Aand 4B and FIGS. 5A through 5E. As shown in FIG. 8B, a buildingextension using 1 twisted pair is provided using, for example, astandard electrical wall box-type Ethernet extension device 10″, asdescribed above in connection with FIGS. 6A through 6D and FIG. 7. Asshown in FIG. 7, a low voltage DC power supply 56 is provided via a walltransformer, as opposed to the standard −48 VDC power input preferred bytelephone companies. The building extension can be useful for industrialcomplexes, schools, railroads, utilities, military sites, airports,hospitals, corporate and government offices, ISPs, and so on.

With continued reference to FIGS. 8C through 8E, a network carrierEthernet extension is shown in FIG. 8C in accordance with anotherexemplary embodiment of the present invention. An Ethernet extensiondevice 10 can be configured on a plug-in card 10′ (e.g., a standard Type400 mechanics card) to map Ethernet packets into 1 to 4 DS1s usingmultilink PPP (e.g., RFCI66I: Point-to-Point Protocol, RFCI 990: PPPMultilink Protocol, and RFC3518: Bridging Control Protocol) fornetwork-wide transport via existing infrastructure. A service conversionEthernet extension device is shown in FIG. 8D in accordance with anotherexemplary embodiment of the present invention. This device 10 can alsobe configured on a plug-in card 10′ (e.g., a standard Type 400 mechanicscard) to map Ethernet packets into 1 to 4 DS1s. Finally, an opticalEthernet extension device is shown in FIG. 8E in accordance with anotherexemplary embodiment of the present invention. This device 10 can alsobe configured on a plug-in card 10′ (e.g., a standard Type 400 mechanicscard) to map Ethernet packets into VT1.5(s) carried over an OC3 orhigher speed (OC12, OC48, etc.) optical link using low order virtualconcatenation, LO-VCAT, ITU G.707 and General Framing Procedure, GFP,ITU G.7041.

It is to be understood that exemplary embodiments of the presentinvention can be embodied as computer-readable codes on acomputer-readable recording medium. The computer-readable recordingmedium is any data storage device that can store data which canthereafter be read by a computer system. Examples of thecomputer-readable recording medium include, but are not limited to,read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetictapes, floppy disks, optical data storage devices, and carrier waves(such as data transmission through the Internet via wired or wirelesstransmission paths). The computer-readable recording medium can also bedistributed over network-coupled computer systems so that thecomputer-readable code is stored and executed in a distributed fashion.Also, functional programs, codes, and code segments for accomplishingthe present invention can be easily construed as within the scope of theinvention by programmers skilled in the art to which the presentinvention pertains.

While the invention herein disclosed has been described by means ofspecific embodiments and applications thereof, numerous modificationsand variations can be made thereto by those skilled in the art withoutdeparting from the scope of the invention as set forth in the claims.

1. An Ethernet extension device for extending Ethernet over twisted paircomprising: an Ethernet port for providing an Ethernet interface forreceiving Ethernet signals from and transmitting Ethernet signals to anEthernet cable connected thereto; a twisted pair port for providing aninterface to tip and ring outside-plant conductors of a telephonenetwork for receiving telephone network signals from and transmittingtelephone network signals to a single twisted pair of the telephonenetwork; a twisted pair transceiver for receiving telephone networksignals from the twisted pair port; an Ethernet transceiver forreceiving Ethernet signals from the Ethernet port, each of the twistedpair transceiver and the Ethernet transceiver being provided withcommunication interface for communicating with each other having acompatible signal converting device for processing, respectively, thetelephone network signals and the Ethernet signals into a compatiblesignal format used by both of the twisted pair transceiver and theEthernet transceiver and for transmitting their respective processedsignals to the Ethernet port and the twisted pair port; and telephonenetwork protection circuitry connected to the twisted pair port forproviding protection against lightning surges and alternating currentpower faults required by the telephone network.
 2. Ethernet extensiondevice as claimed in claim 1, wherein the compatible signal format isHigh-level Data Link Control.
 3. Ethernet extension device as claimed inclaim 1, wherein the twisted pair transceiver is configured to provide adigital subscriber loop (DSL) interface to the telephone network via thetwisted pair.
 4. An Ethernet extension device as claimed in claim 3,wherein the DSL interface is Symmetric High bit-rate DSL (SHDSL).
 5. AnEthernet extension device as claimed in claim 1, wherein the Ethernetport, the twisted pair port, the twisted pair transceiver, the Ethernettransceiver and the telephone network protection circuitry are providedon a single plug-in card dimensioned for deployment in a single cardslot in a shelf of a telecommunications equipment bay.
 6. An Ethernetextension device as claimed in claim 5, wherein the single plug-in carddimensions do not exceed an overall height of about 5.6 inches, andoverall width of about 1.4 inches, and an overall depth of about 6inches.
 7. An Ethernet extension device as claimed in claim 5, whereinthe single plug-in card is configured in one of a standard Type 400™ andType 200™ mechanics circuit board arrangement.
 8. An Ethernet extensiondevice as claimed in claim 1, wherein the Ethernet port, the twistedpair port, the twisted pair transceiver, the Ethernet transceiver andthe telephone network protection circuitry are provided in a standardelectrical wall box.
 9. An Ethernet extension device as claimed in claim8, wherein the wall box is provided with a faceplate having at least oneof a vent and heat sink.
 10. An Ethernet extension device as claimed inclaim 8, wherein the wall box is provided with a face plate comprising apower input and one of an Ethernet connector for connection to theEthernet port and the Ethernet port.
 11. An Ethernet extension device asclaimed in claim 1, wherein the telephone network protection circuitrycomprises at least one sidactor device connected across Tip and Ringconnectors corresponding to the twisted port selected to crossbar from ahigh impedance state into a low impedance state when an overvoltagecondition occurs between at least one of Tip and Ring and ground toshunt surge current to ground, and to transition to the high impedancestate when the shunted current is below a selected threshold.
 12. AnEthernet extension device as claimed in claim 1, further comprising atransformer and an analog front-end circuit connected between thetwisted pair port and the twisted pair transceiver, and wherein thetelephone network protection circuitry comprises a low-capacitancesteering diode/transient voltage suppressor (TVS) array combinationconnected across the analog front-end circuit to shunt surges in excessof a selected level on a power supply rail to the analog front-endcircuit to the supply rail and to shunt surges below the groundreference for the supply rail to ground.
 13. An Ethernet extensiondevice as claimed in claim 1, wherein the telephone network protectioncircuitry comprises first and second fuses provided at respective onesof the Tip and Ring connectors of the twisted pair port, the first andsecond fuses being selected to meet lightning surge and power faultrequirements of the telephone network for outside telephone networkcircuits by opening and protecting telephone network wiring external tothe Ethernet extension device when current shunted to frame ground areof a selected magnitude.
 14. An Ethernet extension device as claimed inclaim 1, wherein the Ethernet port is 4-wire RJ45 connector having atransmit side and a receive side, and wherein the telephone networkprotection circuitry comprises first and second steering diode/transientvoltage suppressor (TVS) array combinations connected respectively tothe transmit side and the receive side and configured to provideovervoltage protection in the event of lightning surges and lightningsurge tests and to meet AC power fault requirements of the telephonenetwork by clamping differential voltage between corresponding ones ofthe four wires when an overvoltage condition occurs that exceeds a TVSbreakdown voltage and shunting the resulting surge current through thecorresponding one of the steering diode/TVS array combinations. 15.Ethernet extension device as claimed in claim 14, wherein the telephonenetwork protection circuitry further comprises first, second, third andfourth fuses provided at respective ones of the four wires of the RJ45connector and selected to open and protect wiring external to theEthernet extension device when current shunted by the first and secondsteering diode/transient voltage suppressor (TVS) array combinations isof a selected magnitude.
 16. Ethernet extension device as claimed inclaim 14, further comprising an Ethernet physical interface circuitconnected between the Ethernet port and the Ethernet transceiver, andwherein the telephone network protection circuitry further comprisesthird and fourth steering diode/transient voltage suppressor (TVS) arraycombinations connected respectively to the transmit side and the receiveside and referenced to power supply rail for the Ethernet physicalinterface circuit, the third and fourth steering diode/TVS arraycombinations being configured to shunt surges in excess of a selectedlevel on the power supply rail to the power supply rail and to shuntsurges below the ground reference for the supply rail to ground by thecorresponding one of the third and fourth steering diode/TVS arraycombinations.